Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

At the radiation source ELBE in the Forschungszentrum Dresden-Rossendorf two free electron lasers (3-20 µm and 20-230 µm) are in routine user operation for a wide range of IR experiments for some years. The lasers are driven by a superconducting RF Linac which permits the generation of a cw-beam with high average beam power. For many experiments the frequency and power stability of the laser beam is of outstanding importance. Therefore studies on fluctuations and drifts in different time scales (from µs to hours) were accomplished and possible causes for these instabilities were investigated. To improve the long and short term stability we developed and implemented active feed back controls for electron energy and thus laser wavelength and out-coupled IR-beam power at ELBE.